I. Field of the Invention
The present invention pertains to a method and apparatus for forming a cube of frozen liquid. More particularly, the present invention pertains to a method and apparatus for forming an ice cube having a discernible monogram.
II. Description of the Prior Art
In the prior art, there are many teachings pertaining to the fabrication of ice cubes. These teachings include methods and apparatus for forming novelty ice cubes. Novelty ice cubes include ice cubes having fanciful shapes. For example, U.S. Pat. Design No. 263,398 to Tiller dated Mar. 16, 1982 shows an ice tray which would appear to form ice cubes having the configuration of the State of Texas. U.S. Pat. No. 2,756,567 to Martin dated July 31, 1956 teaches a freezing tray with a plurality of molds having various fanciful configurations. In these examples of prior art freezing trays, the liquid to be frozen is poured into the mold and the filled mold is placed in a freezer unit where the liquid freezes and assumes the shape of its container.
At this point, it is appropriate to mention the use of the word "cube" throughout this application and the appended claims is used to refer to pieces of ice made for drinks. A common understanding of the word "cube" is intended. Accordingly, the word "cube" is not intended to be limited to a strict geometric definition and is meant to be referred to common pieces of ice for drinks which are rarely geometric cubes. It is well understood that ice cubes come in a variety of geometric shapes which include half moons and rounded cubes.
In making ice cubes with ice trays used in the home, tap water is poured into the tray and the filled tray is frozen with the individual cubes being formed. The tap water which is used to make the ice cubes contains numerous minerals and dissolved gasses. As the ice cube freezes, the presence of these minerals and dissolved gasses causes the completed ice cube to be cloudy. Also, the formation of the ice cube in the common ice tray results in fractures of the ice cube which further makes it cloudy and unclear. The sequence of formation of the ordinary ice cube which is clouded due to fractures and dissolved minerals and gasses is shown in U.S. Pat. No. 3,318,105 to Burroughs et al. dated May 9, 1967.
While ice cubes having contained fractures, dissolved gasses and dissolved minerals are fine for home use, industrial institutions such as restaurants, hotels and cocktail lounges have shown a preference for ice cubes which are clear and free of fractures and dissolved gasses and minerals. To accommodate the desires of these users, various methods and apparatus have been developed to form ice cubes which are crystal clear. These methods include cyclically dipping a die in water or immersing a die in water and agitating the water. An example of the former is shown in U.S. Pat. No. 3,418,823 to Vivai dated May 15, 1967. In this teaching, a plurality of molds are sequentially dipped into a pan of water to form successive ice layers which subsequently grow into an ice cube of desired size. Formation of several ice layers insures the completed ice cube will be transparent. As stated in Vivai, it is also important the water be stirred. An example of the latter is found in U.S. Pat. No. 4,199,956 to Lunde dated Apr. 29, 1980. Paddles are used to agitate the water. In U.S. Pat. No. 2,253,512 to Fechner et al. a propeller stirs a water bath to provide agitation. As noted in U.S. Pat. No. 4,199,956 the art has known that agitation or movement of the water during the freezing is necessary to form the clear ice cube. The agitation washes gasses and minerals away from the surface of the ice cube during its formation. Agitation can be provided through mechanical means such as paddles or it can be provided due to convection currents found in the ice making apparatus. The amount of agitation which is necessary will vary depending upon the chemistry of the water. Namely, the exact amount of agitation must be selected to account for changes in oxygen and other gas content as well mineral content of the water. Commonly, this can be attained through a small amount of trial and error for a particular water source.
Another example of an apparatus for making clear ice cubes is found in U.S. Pat. No. 3,254,501 to Brysselbout dated June 7, 1966. In this technique, water is sprayed into a cavity which is being cooled. Since the water is being frozen while it is motion, a clear ice cube is formed.